Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Seven Sisters: 03-10 (52), 03-11 (51), 03-12 (50), 03-13 (49), 03-14 (47) — by astronomy; check the weather when the night is within four days.

2031-03-03astronomy score per night — click a bar for that night2031-04-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-03-03 Mon	18	—	unknown	19:50–22:40 (marginal, 2.83 h)	72.5° 17:25	9.56	75%	44.0°
2031-03-04 Tue	19	—	unknown	19:50–22:35 (marginal, 2.75 h)	72.5° 17:20	9.52	83%	55.9°
2031-03-05 Wed	22	—	unknown	19:50–22:35 (marginal, 2.75 h)	72.5° 17:15	9.47	89%	68.0°
2031-03-06 Thu	27	—	unknown	19:50–20:10 (good, 0.33 h)	72.5° 17:15	9.42	95%	80.3°
2031-03-07 Fri	32	—	unknown	19:55–21:15 (good, 1.33 h)	72.5° 17:10	9.38	98%	92.8°
2031-03-08 Sat	40	—	unknown	19:55–21:55 (good, 2.0 h)	72.5° 17:05	9.33	100%	105.7°
2031-03-09 Sun	46	—	unknown	19:55–22:00 (good, 2.08 h)	72.5° 17:00	9.28	99%	118.7°
2031-03-10 Mon	52	—	unknown	19:55–22:00 (good, 2.08 h)	72.5° 16:55	9.23	96%	132.0°
2031-03-11 Tue	51	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:55	9.18	91%	145.5°
2031-03-12 Wed	50	—	unknown	20:00–22:00 (good, 2.0 h)	72.5° 16:50	9.14	84%	159.1°
2031-03-13 Thu	49	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:45	9.09	75%	172.2°
2031-03-14 Fri	47	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:40	9.04	65%	171.7°
2031-03-15 Sat	44	—	unknown	20:05–21:50 (good, 1.75 h)	72.5° 16:35	8.99	54%	158.3°
2031-03-16 Sun	42	—	unknown	20:05–21:45 (good, 1.67 h)	72.5° 16:35	8.94	42%	144.3°
2031-03-17 Mon	41	—	unknown	20:05–21:40 (good, 1.58 h)	72.5° 16:30	8.89	31%	130.2°
2031-03-18 Tue	39	—	unknown	20:05–21:35 (good, 1.5 h)	72.5° 16:25	8.84	21%	116.0°
2031-03-19 Wed	37	—	unknown	20:05–21:30 (good, 1.42 h)	72.5° 16:20	8.78	13%	101.9°
2031-03-20 Thu	34	—	unknown	20:10–21:30 (good, 1.33 h)	72.5° 16:20	8.73	6%	87.9°
2031-03-21 Fri	32	—	unknown	20:10–21:25 (good, 1.25 h)	72.5° 16:15	8.68	2%	74.0°
2031-03-22 Sat	31	—	unknown	20:10–21:20 (good, 1.17 h)	72.5° 16:10	8.63	0%	60.3°
2031-03-23 Sun	29	—	unknown	20:10–21:15 (good, 1.08 h)	72.5° 16:05	8.58	1%	46.9°
2031-03-24 Mon	27	—	unknown	20:15–21:15 (good, 1.0 h)	72.5° 16:00	8.52	4%	33.9°
2031-03-25 Tue	23	—	unknown	20:15–21:05 (good, 0.83 h)	72.5° 16:00	8.47	8%	21.2°
2031-03-26 Wed	20	—	unknown	20:15–21:00 (good, 0.75 h)	72.5° 15:55	8.42	15%	9.2°
2031-03-27 Thu	16	—	unknown	20:20–20:50 (good, 0.5 h)	72.5° 15:50	8.36	22%	5.7°
2031-03-28 Fri	13	—	unknown	20:20–20:35 (good, 0.25 h)	72.5° 15:45	8.31	31%	16.6°
2031-03-29 Sat	10	—	unknown	20:20–21:20 (marginal, 1.0 h)	72.5° 15:40	8.26	40%	28.2°
2031-03-30 Sun	8	—	unknown	21:20–22:10 (marginal, 0.83 h)	72.5° 16:40	8.2	49%	40.0°
2031-03-31 Mon	6	—	unknown	21:25–22:05 (marginal, 0.67 h)	72.5° 16:35	8.15	59%	51.8°
2031-04-01 Tue	5	—	unknown	21:25–22:00 (marginal, 0.58 h)	72.5° 16:30	8.09	68%	63.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-03-03&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.